Rotary tool attachment for chain saw motor

ABSTRACT

A rotary tool attachment for a chain saw motor drive unit, where such unit includes a motor housing and a motor-driven shaft protruding to one side of the housing and mounting a chain saw sprocket. The attachment comprises an elongated support adapted to be secured to the housing with such normal to the driven shaft of the drive unit. A tool-driving sprocket adjacent the end of the support remote from the driven shaft and in the plane of the chain saw sprocket is mounted on a power transmission input shaft which generally parallels the motor-driven shaft. The input shaft extends into a tool-housing assembly mounted on the remote end of the support and is connected through a power-transmitting means with right-angle drive train to a tool-driving head journaled on the tool housing assembly.

United States Patent [72] Inventor William F. Matthews Rte. 2, Box 1061, Coos Bay, Oreg. 97420 [21] Appl. No. 823,912 [22] Filed May 12, 1969 [45] Patented May 25, 1971 [54] ROTARY TOOL ATTACHMENT FOR CHAIN SAW MOTOR 8 Claims, 2 Drawing Figs.

[52] [1.8. CI 173/29, 143/32 [51] Int. Cl B27b 17/00 [50] Field of Search 173/29, 46; 143/32 [56] References Cited UNITED STATES PATENTS 2,526,131 10/1950 Hamish et al 173/29X 2,676,628 4/1954 Hastain 2,783,794 3/1957 Kroll Primary Examiner-Ernest R. Purser Attorney-Kolisch & Hartwell ABSTRACT: A rotary tool attachment for a chain saw motor drive unit, where such unit includes a motor housing and a motor-driven shaft protruding to one side of the housing and mounting a chain saw sprocket. The attachment comprises an elongated support adapted to be secured to the housing with such normal to the driven shaft of the drive unit. A tool-driving sprocket adjacent the end of the support remote from the driven shaft and in the plane of the chain saw sprocket is mounted on a power transmission input shaft which generally parallels the motor-driven shaft. The input shaft extends into a tool-housing assembly mounted on the remote end of the support and is connected through a power-transmitting means with right-angle drive train to a tool-driving head joumaled on the tool housing assembly.

ROTARY TOOL ATTACHMENT FOR CHAIN SAW MOTOR This invention relates to an attachment for a chain saw motor drive unit. More particularly, it relates to such an attachment wherein a chain saw drive unit may be used to power a rotary tool.

In logging and other operations, heavy equipment, such as cranes and large trucks, are used which often need repairs in the field. These repairs may require the use of power-operated rotary tools, such as impact wrenches but the usual power sources for such tools (air under pressure or electricity) generally are not at hand. I have found that in many such operations, hand-held chain saws are readily available, and may be relied upon to power the repair tools needed.

A general object of this invention is to provide a novel attachment for a chain saw motor drive unit which may be secured to the housing of the unit to convert the chain saw into a power-operated rotary tool. I

More specifically, an object of the invention is to provide such an attachment featuring a tool-driving sprocket adapted to assume aposition substantially in the plane of the chain saw sprocket which is normally a part of any chain saw motor drive unit. A rotatable tool-driving head is included which rotates about an axis normal to the axis of the tool-driving sprocket. Forming an operative connection between the tool-driving sprocket and tool-driving head is a power-transmitting means with right-angle drive train. The organization outlined permits a tool to be formed upon conversion of a chain saw where the tool-driving head is disposed forwardly of the motor drive unit and the axis of rotation of this driving head parallels the plane of the chain saw driving sprocket, and extends in a fore-andaft direction.

The invention also contemplates the provision of a housing assembly which mounts the rotatable driving head, The housing assembly is detachably mounted on the remote end of a support which joins the housing assembly to the motor drive unit, and the housing assembly can be turned in a novel manner and remounted on the support to change the direction which the driving head faces. This is advantageous in performing work operations where clearance or other problems make it desirable to have the driving head in a position other than disposed forwardly of the motor drive unit.

A further feature of the invention is the provision, in a power-transmitting means which connects a tool-driving sprocket in the attachment with the rotatable driving head, of reversing means whereby the direction of rotation of the driving head may be reversed when desired.

Other objects and advantages of the invention will become more fully apparent as the following description is read in conjunction with the accompanying drawings, wherein:

FIG. 1 is a top plan view of a chain saw motor drive unit having an attachment as contemplated by the invention secured to the housing of the drive unit and showing an elongated housing assembly in the attachment extending forwardly of the drive unit; and

FIG. 2 is a side view of the drive unit and attachment shown in FIG. I, differing from FIG. I in that the housing assembly is oriented in a different direction.

Referring now to the drawings, at is indicated generally the motor drive unit of a conventional chain saw. The saw chain and bar have been removed from the unit. The unit includes the usual motor housing I], with a handgrip 12 at the rear of the unit, and a handgrip bar 14 extending substantially around its forward end. A chain saw sprocket 16 is disposed on one side of the housing, such being mounted on a motor driven shaft 17 which is connected to the usual motor within the housing. Guard shield 18 secured to housing 11 provides a protective cover over sprocket 16.

The attachment of the invention is indicated generally at 20. The attachment includes an elongated support, or support plate, 22 which is secured to housing 10 and projects forwardly therefrom. The connection between the support and housing is made by a pair of bolts 24 that extend through an elongated slot 26 in the support and that have inner threaded ends screwed into accommodating bores in the housing. Slot 26 permits limited adjustable movement of the support relative to the housing on loosening of bolts 24.

Located forwardly of the motor drive unit and inwardly of support 22 is an elongated housing assembly 28. In FIG. 1, housing assembly 28 is shown with its longitudinal axis 281: generally paralleling the longitudinal axis of support 22 and paralleling an axis extending from the rear to the front of the motor drive unit. The assembly is secured against the inner side of support 22 by means of fasteners 30 screwed into accommodating internally threaded bores provided in shell portion 32 of the housing assembly.

The housing assembly illustrated comprises two sections detachable joined together. Specifically, the forward part of the housing assembly comprises a section 34 which houses the operating parts of a conventional impact wrench mechanism. Journaled at the forward extremity of section 34 is what is described as a driving head 36 which is rotated with operation of the impact wrench mechanism in a conventional manner.

Also part of the housing assembly is a rear section 38 which is fastened to the forward section enclosing the impact wrench mechanism by fasteners 40 joining flange 34a of the forward section with flange 38a of the rear section. The rear housing section, as illustrated in HQ 1, comprises two opposed and matching casing parts 41, 42 (casing part 42 including the shell portion 32 earlier described) suitably secured together by fasteners 44.

Journaled within the rear housing section 38 is a powertransmission input shaft designated at 50. This shaft, as can be seen in FIG. 1, generally parallels the motor-driven shaft 17 of the chain saw motor drive unit. Shaft 50 projects beyond the outer side of support 22 adjacent the remote end of this support. Mounted on the end of the shaft is a tool-driving sprocket 52 which is generally in the plane of chain saw sprocket 16 of the motor drive unit.

Power is transmitted from the chain saw sprocket to sprocket 52 by a flexible chain, such as the one shown at 54, which is trained over the two sprockets, If desired, a bar such as that shown at 56 in 'FIG. 2 may be included replacing the usual bar of the chain saw and suitably fastened to the housing of the motor drive unit to guide runs of the chain 54 where they extend between the sprockets 16, 52.

The usual impact wrench mechanism includes a rotatable shaft, such as the one shown at 58 in a broken-away portion of FIG. I, which when rotated, and through the operating parts of the impact wrench mechanism, supplies a driving torque to driving head 36 disposed at the forward end of the mechanism. As contemplated by this invention, power-transmitting means, shown generally at 60, is provided within the rear housing section 38. The power-transmitting means includes a right-angle drive train operatively connecting, for driving purposes, power transmission input shaft 50 with shaft 58 of the impact wrench mechanism. As also will be apparent on such transmitting means being described, the transmitting means includes a reversing transmission which is operable to affect a change in the direction that shaft 58 is rotated by input shaft 50, such being effective to change the rotational direction of driving head 36.

Further describing power-transmitting means 60, shown at 64 is the splined section of a shaft which has its forward end suitably coupled to shaft 58 whereby the two shafts rotate as one. .loumaled within the housing for rotation about the axis of shaft 64 are a pair of axially spaced, opposed bevel gears 66, 68. Bevel gears 66, 68 mesh with another bevel gear 70 which is mounted on and secured to shaft 50 to rotate with this shaft.

Mounted for axial shifting movement on the splined section of shaft 64 and disposed between bevel gears 66, 68 is a collar 72. Such has internal splines meshing with the splines of the shaft whereby the collar and shaft 64 rotate as one. Dogs, such as those shown at 74, 76, are provided on opposite ends of collar 72. With the collar in the position shown in FIG. 1, dog 74 engages notch 78 of bevel gear 66, whereby a driving torque may be transmitted from shaft 50, through bevel gear 66, to shaft 58 of the impact wrench mechanism. Utilizing a shifter 80, the collar may be shifted axially to the right in FIG. I to cause dog 76 to engage notch 82 of bevel gear 68 whereby driving torque may be transmitted to shaft 58 from shaft 50 through bevel gear 68 With drive derived through bevel gear 68, shaft 58 is rotated in a direction opposite to the direction that it rotates when drive is derived through bevel gear 66.

To effect shifting of the shifter 80, a handle 84 is provided on the outside of housing section 38 which is manipulatable by the operator of the attachment.

With the attachment setup as illustrated in FIG. 1, the elongated housing assembly 28 extends forwardly of the motor drive unit and, in effect, forms a forward extension of support 22. Tool-driving head 36 is carried at the forward extremity of this housing assembly and such is rotatable about an axis which extends from the rear to the front of the motor drive unit normal to the drive shaft 17 of the unit. The entire motordriven assembly,'comprising the drive unit and attachment, may be readily manipulated by an operator to tighten or loosen nut connections with the particular fastener worked upon being located substantially directly in front of the motor drive unit, which is the most convenient position for working on such fasteners with the assembly manipulated using handles 12, 14 of the drive unit. The rotational direction of the driving head is controlled with handle 84.

As contemplated by this invention the housing assembly may be detached from support 22, and rotated 90 about the axis of transmission input shaft 50 to orient the housing assembly with respect to the support as shown in FIG. 2. The housing assembly may then be resecured to the support using fasteners 30 (the fasteners 30 and the accommodating bores in housing section 38 being symmetrically positioned in such a manner as to permit such reattachment). The housing assembly 28 in FIG. 2 has its longitudinal axis generally normal to an axis extending from the rear to the front of the motor drive unit. With the assembly so positioned the driving head faces downwardly with respect to the motor drive unit rather than forwardly as in FIG. 1. Turning of the housing assembly in this manner in no way effects the operation of the powertransmitting means 60 and the driving relationship established between shaft 50 and shaft 58 of the impact wrench mechanism. Such shifting of the housing assembly while placing the driving head at a somewhat less convenient working position is desirable in that it permits working on fasteners where there are certain limitations with respect to working space about the fasteners.

The attachment contemplated is versatile in operation and when mounted on the drive shaft unit of a chain saw provides a power-operated rotary tool where conventional power sources are not available.

Further, with the housing assembly of the attachment mounted on the inner side of the support plate, it isadjacent the fore-to-aft centerline of the chain saw motor drive unit to provide a well-balanced and easily manipulated tool.

While an embodiment of the invention has been described, obviously changes and variations are possible without departing from the invention.

It is claimed and desired to secure by Letters Patent:

1. A rotary tool attachment for a chain saw motor drive unit where such unit includes a motor, a motor housing, a motordriven shaft connected to the motor and protruding to one side of the motor housing and a chain saw sprocket outside the motor housing joined to said shaft, said attachment comprising in operative position,

an elongated support secured to said motor housing in a position extending normal to said shaft and having a remote end located forwardly of said housing;

a tool-driving sprocket adjacent the remote end of said support generally in the plane ofsaid chain saw sprocket;

a power transmission input shaft mounting said tool-driving sprocket, said input shaft generally paralleling the motordriven shaft;

a tool-housing assembly mounted on the remote end of said support receiving said transmission input shaft;

releasable fastening means securing said housing assembly to said support, said fastening means when released permitting swinging of said housing assembly about the axis of said input shaft to different positions;

a rotatable tool-driving head mounted on said housing assembly rotatable about an axis which is maintained substantially normal to the axis of said transmission input shaft with said housing assembly in any of said different positions; and

a power-transmitting means with right-angle drive train within said housing assembly operatively connecting said input shaft and said driving head for producing rotation of said driving head about its axis upon rotation of said input shaft with the housing assembly in any one of said different positions.

2. The attachment of claim 1, wherein said tool-housing assembly comprises an elongated assembly which forms a forward extension of said support when said housing assembly is in a position where the axis of the driving head extends forwardly of said input shaft.

3. The attachment of claim 1, wherein the housing assembly includes a first housing section mounting said driving head and enclosing impact wrench mechanism, and further includes a second housing section fastened to the first which encloses said power transmitting means.

4. The attachment of claim 1, wherein said power-transmitting means includes a reversing transmission to effect a change in the direction of rotation of said driving head with the direction of rotation of said input shaft maintained the same.

5. The attachment of claim 1, wherein said tool-driving sprocket is disposed on the outer side of said support, and said housing assembly is mounted adjacent the inner side of said support, to be nearer an axis passing through the center of said motor drive unit and paralleling said support and tool-driving sprocket.

6. A rotary tool attachment for a chain saw motor drive unit where such unit includes a motor, a motor housing, a motordriven shaft connected to the motor and protruding to one side of the motor housing and a chain saw sprocket outside the motor housing joined to said shaft, said attachment comprising, in operative position,

an elongated support secured to said motor housing in a position extending normal to said shaft and having a remote end located forwardly of said housing;

a tool-driving sprocket adjacent the remote end of said support and on-the outer side of said support generally in the plane of said chain saw sprocket;

a power transmission input shaft mounting said driving sprocket, said input shaft generally paralleling the motordriven shaft;

a tool-housing assembly mounted adjacent the remote end of said support on the inner side of said support to be near an axis passing through the center of said motor-driven unit, said housing assembly receiving said transmission input shaft;

a rotatable tool-driving head mounted on said housing assembly rotatable about an axis normal to the axis of said transmission input shaft; and

a power-transmitting means with right-angle drive train within said tool-housing assembly connecting said input shaft and said driving head for producing rotation of said driving head about its axis on rotation of said input shaft, including a reversing transmission to effect a change in the direction of rotation of said driving head with the direction of rotation of said input shaft maintained the same.

7. The attachment of claim 6, wherein said tool-housing assembly is mounted for swinging to difierent positions about the axis of said transmission input shaft, and said right-angle drive means comprises intermeshing bevel gears operatively interconnecting said input shaft and tool-driving head operable to transmit torque therebetween with the housing assembly in any of said different positions. 

1. A rotary tool attachment for a chain saw motor drive unit where such unit includes a motor, a motor housing, a motor-driven shaft connected to the motor and protruding to one side of the motor housing and a chain saw sprocket outside the motor housing joined to said shaft, said attachment comprising in operative position, an elongated support secured to said motor housing in a position extending normal to said shaft and having a remote end located forwardly of said housing; a tool-driving sprocket adjacent the remote end of said support generally in the plane of said chain saw sprocket; a power transmission input shaft mounting said tool-driving sprocket, said input shaft generally paralleling the motordriven shaft; a tool-housing assembly mounted on the remote end of said support receiving said transmission input shaft; releasable fastening means securing said housing assembly to said support, said fastening means when released permitting swinging of said housing assembly about the axis of said input shaft to different positions; a rotatable tool-driving head mounted on said housing assembly rotatable about an axis which is maintained substantially normal to the axis of said transmission input shaft with said housing assembly in any of said different positions; and a power-transmitting means with right-angle drive train within said housing assembly operatively connecting said input shaft and said driving head for producing rotation of said driving head about its axis upon rotation of said input shaft with the housing assembly in any one of said different positions.
 2. The attachment of claim 1, wherein said tool-housing assembly comprises an elongated assembly which forms a forward extension of said support when said housing assembly is in a position where the axis of the driving head extends forwardly of said input shaft.
 3. The attachment of claim 1, wherein the housing assembly includes a first housing section mounting said driving head and enclosing impact wrench mechanism, and further includes a second housing section fastened to the first which encloses said power transmitting means.
 4. The attachment of claim 1, wherein said power-transmitting means includes a reversing transmission to effect a change in the direction of rotation of said driving head with the direction of rotation of said input shaft maintained the same.
 5. The attachment of claim 1, wherein said tool-driving sprocket is disposed on the outer side of said support, and said housing assembly is mounted adjacent the inner side of said support, to be nearer an axis passing through the center of said motor drive unit and paralleling said support and tool-driving sprocket.
 6. A rotary tool attachment for a chain saw motor drive unit where such unit includes a motor, a motor housing, a motor-driven shaft connected to the motor and protruding to one side of the motor housing and a chain saw sprocket outside the motor housIng joined to said shaft, said attachment comprising, in operative position, an elongated support secured to said motor housing in a position extending normal to said shaft and having a remote end located forwardly of said housing; a tool-driving sprocket adjacent the remote end of said support and on the outer side of said support generally in the plane of said chain saw sprocket; a power transmission input shaft mounting said driving sprocket, said input shaft generally paralleling the motor-driven shaft; a tool-housing assembly mounted adjacent the remote end of said support on the inner side of said support to be near an axis passing through the center of said motor-driven unit, said housing assembly receiving said transmission input shaft; a rotatable tool-driving head mounted on said housing assembly rotatable about an axis normal to the axis of said transmission input shaft; and a power-transmitting means with right-angle drive train within said tool-housing assembly connecting said input shaft and said driving head for producing rotation of said driving head about its axis on rotation of said input shaft, including a reversing transmission to effect a change in the direction of rotation of said driving head with the direction of rotation of said input shaft maintained the same.
 7. The attachment of claim 6, wherein said tool-housing assembly is mounted for swinging to different positions about the axis of said transmission input shaft, and said right-angle drive means comprises intermeshing bevel gears operatively interconnecting said input shaft and tool-driving head operable to transmit torque therebetween with the housing assembly in any of said different positions.
 8. The attachment of claim 7, which further comprises releasable fastening means for securing said tool-housing assembly to said support in different ones of said positions. 